This invention relates to a cloth spreading machine, and more particularly to a cloth spreading machine which will accurately spread layers of cloth without a catcher mechanism, in a face-to-face mode, or a face-up or face-down mode.
Heretofore, in cloth spreading machines for reciprocably spreading layers of cloth longitudinally upon a cloth supporting surface such as a cutter table, the ends of the spread layers have been mainained in substantially vertical alignment by various types of catcher mechanisms, which cooperate with the spreader elements on the machine at the end of each spreading traverse for clamping the ends of the cloth upon the cutting table.
One example of such a cloth spreading machine for spreading the cloth face-to-face, in cooperation with a catcher mechanism is the Martin et al. U.S. Pat. No. 3,400,927.
An example of a prior cloth spreading machine for spreading cloth face-up or face-down, in which a cutting apparatus is utilized in cooperation with the spreader element in which a catcher mechanism is utilized, is the Martin et al. U.S. Pat. No. 3,503,604. The Martin et al. U.S. Pat. No. 3,503,604 incorporates a hinged spreader blade adapted to be forced down by the weight of the catcher bar in order to place the cut end of the cloth as close as possible to vertical alignment with the cut ends of the previously spread layers of cloth.
Typically, it is difficult to spread layers of cloth so that the ends of the layers are in substantial vertical alignment, when no catcher mechanism of any type is utilized. One difficulty lies in cutting the cloth transversely so that the cut end of the cloth is positioned accurately in a vertical plane containing the other cut ends of the previously spread cloth layers. Another difficulty arises in maintaining uniform tension in the cloth. A further difficulty occurs in attempting to eliminate or even minimize slack in the cloth, particularly very thin cloth, because of the wind or air movement developed against the cloth while being suspended or supported in a longitudinally movable cloth spreader frame. Moreover, the weight, density, and thickness of the cloth to be spread affect the tension and slack in the cloth as well as the degree of control required to feed, support, cut and position the cloth without a catcher mechanism.
In order to accurately position a layer of cloth upon the cutting table or previously spread layers, without a catcher mechanism, it is vitally important that the difference in elevation between the spreader element or the cutter knife and top layer of cloth be maintained substantially uniform continuously.
Heretofore, in cloth spreading machines, the height of the spreader blade or spreader element has been adjusted or elevated by various mechanical devices. One common method of elevating the cloth spreader blade is to provide a cam mechanism on the catcher at one end of the cutting table for engagement by the spreader element to elevate the spreader blade incrementally, such as illustrated in the above Martin et al. U.S. Pat. Nos. 3,400,927 and 3,503,604. Thus, as the cloth spreading machine travels the full length of the cutting table, back and forth, and spreads a sufficient number of layers of cloth, the spreader blade automatically rises a uniform increment of height. Since the compressibility and thickness of the cloth layers varies with the different types of cloth to be spread, the number of layers required to elevate the spreader blade one increment varies.
Another method of elevating the cloth spreader blades is to provide an elevator mechanism which can be raised or ratcheted upward by some type of sensor finger or feeler which is automatically forced upward by the increasing height of the cloth layers, such as disclosed in the Shapera U.S. Pat. Nos. 1,067,379; 1,131,647, or 1,531,313. This type of cloth spreader blade elevating mechanism does not produce uniform spacing between the spreader blade and the top cloth layer, because of the pliability and compressibility of the cloth layers.
Various types of tension rollers and wrap rollers have been utilized in cloth spreading machines for attempting to maintain substantially uniform tension in the cloth as it is fed through the cloth spreading machine, and for maintaining a substantial arc of wrap about a driven top feed roller in the cloth spreading machine. One example of a cloth spreading machine incorporating a pivotal wrap frame incorporating wrap rollers for being moved into engagement with a top feed roll in operative position and for swinging away from engagement to permit threading of the cloth web, in the Deichmann U.S. Pat. No. 3,094,319, issued June 18, 1963, for TURNTABLE CUTTING MACHINES. However, the Deichmann patent does not disclose any type of pinch roller for engaging the wrapped portion of the cloth web about the top feed roll. Pivotal pinch rollers for engaging cloth feed rolls per se are old, as illustrated in the Bloch U.S. Pat. No. 1,841,703 and the Sayles U.S. Pat. No. 2,478,840.
Although wind break devices have been utilized in cloth spreading machines before, nevertheless such wind break devices have been solid, fixed objects which have been positioned substantially behind the vertical path of the cloth feed web because of the necessity of the cloth spreader element to be vertically movable.